Avoid using Mana Tea when debuffs are going out as you might have to move

Make sure you can see the necrotic debuff on your frames so you don’t waste mana healing immune people

Life Cocoon can help to save someone with necrotic debuff as the absorb portion still works

Be very careful with Roll. You need to stay close to your raid, and on Mythic difficulty you will be escorted out to drop your debuff and will have to stay close to your escort and second debuff target. Rolling could cause a wipe. On heroic, you can use roll to get out to drop your debuff and back in again, however.

You can set up Transcendence to get back to raid quickly after dropping your debuff (but be careful on Mythic as you don’t want to cause problems for your escort).